Cerebellar Injury in Children with Cerebral Palsy, 4/2005

SUMMARY:

These two small studies looked at injury to the cerebellum in children with cerebral palsy associated with very early prematurity and low birth weight. They found that nearly half of these children with cerebral palsy had cerebellar injury as well as cerebral injury. Those with injuries in both structures had much less chance of becoming walkers or talkers than those with cerebral injuries alone.

The Cerebellum (meaning the "little brain") is a critical part of the brain located just under the cerebrum. It is a paired structure about the size of two small plums which plays a major role in coordinating voluntary motor activity (and according to more recent research, coordinating thought processes as well). Injuries to the cerebellum produce movement disorders included among the "cerebral palsies." These have traditionally featured ataxia (an inability to coordinate voluntary movements) and decreased muscle tone (the opposite of spasticity). These are features usually seen in adults with cerebellar disorders including stroke, tumors, and multiple sclerosis.

Two recent articles written by the same group redirect our attention to cerebellar injury in children with cerebral palsy. Both focus on surviving premature infants born before 28 weeks of gestation or weighing less than 1000 grams (about 2 pounds) who display cerebral palsy and have cerebellar injury visualized on Magnetic Resonance Imaging (MRI). The first describes the impairments seen in of 10 of these children.  All had a mixture of movement disorders including spasticity, ataxia and dystonia (a form of increased muscle tone distinct from spasticity). All had severe disabilities. None had decreased muscle tone.

In the second study, the authors reviewed the available medical records of infants from the Phoenix, Arizona area born before 28 weeks of gestation or weighing less than 1000 grams who developed cerebral palsy and had been evaluated with MRI. Sixty-seven children met these inclusion criteria. Thirty (45%) had cerebellar injury. PVL (Periventricular leucomalacia: damage to white mater adjacent to the cerebral ventricles) occurred among 67% of the infants with cerebellar injury and 78% of those without cerebellar injury. PVL is the most common abnormality leading to the spastic forms of cerebral palsy, especially diplegia where children have weakness and spasticity involving the legs more than the arms. Children in this study with cerebellar injury were less likely to display diplegia and surprisingly only three of them displayed ataxia. However, children with cerebellar injury were less likely to be able to walk (59%) or talk (77%) than those without cerebellar injury (24% and 17% respectively).

COMMENT:

These are both small studies. But as the history of medical science goes, it is the small pilot studies that drive innovation. The studies suggest that injury to the cerebellum adds significantly to the total disability in children with cerebral palsy. Even with PVL, children may do better if the cerebellum is not also injured. This observation could lead to an additional focus for research on the development.

Bodensteiner JB, Johnson SD: Cerebellar injury in the extremely premature infant: Newly recognized by relatively common outcome.

J Child Neurol

Dec 2004; 19(12):139-142.

Johnson SD, Bodensteiner JB, Lotze TE: Frequency and nature of cerebellar injury in the extremely premature survivor with cerebral palsy: J Child Neurol

Jan 2005; 20(1): 60-64.